The work is concerned with the hormonal regulation of follicular and luteal growth and regression. Representative projects include: determination of hormone levels in unilaterally ovariectomized hamsters- acute and chronic studies; dissociation of the proestrous surges of FSH and LH and the hormonal basis for separate control mechanisms; follicle kinetics as determined by incorporation of 3H Thymidine (autoradiography) into the ovary of intact, unilaterally ovariectomized, PMS-treated, hypophysectomized hamsters; can prolactin directly modulate the response of gonadotropins on follicular development?; comparison of hormone levels in pregnant, pseudopregnant and hysterectomized hamsters; comparison of hormone levels in intact or hypophysectomized (day 12) pregnant rats; does estrogen have a direct luteotropic and luteolytic effect - depending on the stage of pregnancy - on corpora lutea?